Esophageal atresia is a serious birth defect in which the esophagus, the long tube connecting the mouth to the stomach, is segmented and does not form a continuous passageway into the stomach. In particular, infants suffering from esophageal atresia are born with separate upper and lower esophageal portions (commonly referred to as esophageal sacs). In most forms of esophageal atresia the upper esophageal sac begins to fill with mucus and saliva shortly after birth. Consequently, excessive drooling, choking, and coughing are symptomatic of esophageal atresia. Moreover, an infant afflicted with this disorder instantaneously returns (i.e., expels) what he or she is fed, thereby preventing the digestion and absorption of orally administered foods.
There are several types of esophageal atresia. In one type, the upper and lower esophageal sacs are not attached to the trachea. That is, the lower esophageal sac does not develop an esophagotracheal fistula. In another type, the upper esophageal portion ends as a blind sac, whereas the lower esophageal portion is connected to the trachea by a narrow canal at a point just above the tracheal bifurcation. In yet another type, the narrow canal between the trachea and the distal portion of the esophagus forms a ligamentous cord. In rare instances, both the proximal and distal portions of the esophagus actually open into the trachea.
For a period of about three months after birth, the esophageal sacs spontaneously undergo a period of rapid growth toward each other. A number of different techniques have been used during this spontaneous growth period to achieve a more rapid approximation of the esophageal sacs. These techniques have included, for example, the use of large external electromagnet or surgical techniques.
One such technique is described in detail in U.S. Pat. No. 3,986,493 (hereinafter “the '493 patent”), titled “Electromagnetic Bougienage Method.” The '493 patent generally describes a method of preparing an infant for a subsequent primary anastomosis without tension. In particular, the '493 patent describes the use of an external annular electromagnet to intermittently magnetize bougies located within each esophageal sac. Over a period of time, the intermittent force created between the bougies causes the lengthening of the atretic segments. Once the atretic segments are sufficiently lengthened to allow a primary anastomosis, the magnetic bougies are removed and the esophagus is surgically joined.
Yet another method of treating esophageal atresia involves surgically applying sutures to the opposing ends of the esophageal sacs. The sutures create traction forces to the ends of the esophageal sacs during the rapid growth period, thereby causing further elongation of the esophageal sacs. Ultimately, the sutures cause the esophageal sacs to grow together.
The above-described conventional methods of correcting esophageal atresia present several drawbacks. The use of an external electromagnet requires that the infant be placed in a specially constructed bed having a large annular electromagnet. In addition to the expense associated with providing such a bed, the electromagnet itself can significantly impact the ability of caregivers to nurture the infant. In addition, the use of an external electromagnet requires a subsequent procedure to surgically join the esophageal sacs into a continuous lumen. Surgically joining the esophageal sacs requires great surgical skill, and can present significant operative and post-operative complications. For example, surgical joining can result in the misalignment of the esophagus, and consequently, difficulty swallowing. Additional complications include gastroesophageal reflux, which can lead to ulcers in the lower part of the esophagus.
Applying traction through surgically placed sutures also presents several drawbacks. The main drawback of using sutures is the need for a significant surgical procedure once the esophageal sacs are sufficiently lengthened by the traction. This procedure involves surgically joining the esophageal sacs, which can result in a number of the complications detailed above. Moreover, as the sutures draw the esophageal sacs together, the sutures frequently tear out of one or both of the sacs. This requires at least one, and often multiple additional surgeries to re-suture the esophageal sacs.